Competing Reactions Affecting Delignification in Pulping Systems

Abstract

Reactions of l-(4-guaiacyl)-2-(O-guaiacyl)-l,5-pentanediol (1) provide information on the relative rates of pulping reactions that involve quinone methides (QM). The lignin model was treated with 2,6-xylenol, 1,5-anhy-drocellobiitol, amylose, and amines; the levels of fragmentation and cycliz-ation were determined. The results indicate that condensation reactions between the QM derived from 1 and phenolates or carbohydrates are much slower than fragmentation reactions of 1 with sulfide or anthrahydroquinone. The addition of amines to soda cooks of 1 provided little additional model fragmentation; instead, a vinyl ether was observed in substantial amounts.